The removal of phosphorus containing compounds from liquid hydrocarbons and fractions that are used to make hydrocarbon fuels, such as kerosene, gasoline, jet fuel, diesel, etc., is often necessary to meet certain requirements.
Hydrocarbon effluent from a propylene metathesis production process or olefin conversion technology is one of the feedstocks that may be blended together with other hydrocarbon fractions to make other products, such as gasoline.
Hydrocarbon effluent from these processes may be a byproduct of a butenes-producing process that relies on the dimerization of ethylene. When catalysts using phosphorus-based ligands are used in the butenes-producing process, the resulting liquid hydrocarbon may contain phosphorus compounds, for example, as free ligands. In some instances, the presence of these phosphorus compounds may make the liquid hydrocarbon less suitable for blending into gasoline or other products.
For example, ethylene dimerization reactions typically utilize a catalyst to produce butenes, along with higher molecular weight hydrocarbon byproducts and catalyst decomposition products to form a liquid hydrocarbon, as shown in the following scheme:

When the reaction is undergoing this dimerization of ethylene into butene, at least a portion of the catalyst decomposition byproducts may remain soluble in the reaction mixture. As a result, the liquid hydrocarbons, which may include longer chain hydrocarbon byproducts, may contain relatively high levels of phosphorus after separation. The presence of the phosphorus at certain levels can be disadvantageous, because if the liquid hydrocarbon is added to gasoline, the phosphorus content of the gasoline mixture may exceed the pipeline specification limit of 0.0038 gram per gallon. Therefore, in order to allow the liquid hydrocarbon to be blended with gasoline in refinery processing, the phosphorus content of the byproduct should, in some instances, be below 35 wtppm. When this threshold is exceeded, the amount of the byproduct that can be added to the gasoline is reduced, which may negatively impact the economics of the process.
Processes for reducing the content of phosphorus containing compounds have been devised, including distillation and treatment with an oxidizing agent to convert the phosphorus containing compounds to oxides, a portion of which can be removed due to their higher water solubility. These processes, however, typically are expensive, time-consuming, multi-step, and/or high temperature procedures.
Methods for effectively and efficiently reducing the concentration of phosphorus in liquid hydrocarbons are therefore desirable.